Maimonides (1135-1204) was one of these wise old Jews who quotes with approval from a Rabbi of old who had counselled his students : " Teach thy tongue to say, I do not know." Knowing thus the limitations of his own knowledge, it is not surprising that Maimonides should have left a series of practical observations for the maintenance of. health which represent the common sense of all time in the matter. Maimonides anticipated the modern rule for taking fruits before meals, as we all do now at breakfast, and so often as fruit cocktails at the beginning of other meals. He thought that grapes, figs, melons, should be taken before meals, and not mixed with other food. He set down as a rule that what was easily digestible should be eaten at the beginning of the meal, to be followed by what was more difficult of digestion. He declared it to be an axiom of medicine " that so long as a man is able to be active and vigorous, does not eat until he is over full, and does not suffer from constipation, he is not liable to disease".

Salerno's influence was felt much more deeply on surgery than on medicine, as can be seen very clearly from the chapter on Medieval Surgeons— Italy. These great surgeons of the period were also the leaders in medicine—for almost needless to say, there was no separation between the two modes of practice—men were as a rule both physicians and surgeons, even though for us their most important work by far was done in surgery. Certain passages from the works of these great surgeons that have come down to us deserve a place in the treatment of the more distinctly medical questions of the time.

Lanfranc the great French surgeon's description of the treatment of the bite of a rabid dog is interesting. He suggests that a large cupping-glass should be applied over the wound, so as to draw* out as much blood as possible. After this the wound should be dilated and thoroughly cauterized to its depths with a hot iron. It should then be covered with various substances that were supposed " to draw," in order as far as possible to remove the poison. His description of how one may recognize a rabid animal is rather striking in the light of our present knowledge, for he seems to have realized that the main diagnostic element is a change in the disposition of the animal, but above all a definite tendency to lack playfulness.

Lanfranc had manifestly seen a number of cases of true rabies, and describes and suggests treatment for them, though evidently without very much confidence in the success of the treatment.

The treatment of snake-bites and the bites of other animals supposed to be poisonous, or at least suspicious, followed the principles laid down for handling the bite of a mad dog. This was the case particularly as to the encouragement of free bleeding and the use of the cautery.

A characteristic example of the power of clinical observation of the medieval physicians, and one which illustrates much better than many of the absurd tales told as typical of their superstitious tendencies, but really representing that tendency always present in mankind to believe wonders, is to be found in how much they learned of rabies. Even in our own time there are many absurd beliefs with regard to this disease, with some denials of its existence and many grossly exaggerated tales, widely believed; yet the medieval people seem to have reached some quite rational notions with regard to it. Bartholomseus Anglicus is the author of a popular encyclopedia which was very widely read in the medieval period. He was an English Franciscan of the thirteenth century, who gathered together a lot of information and wrote a volume that for centuries after his time, even down to Shakespeare's boyhood, was popular in England.

Here is his description of rabies as he knew it. The most important element is his recognition of the uncertainty of the length of the incubation period, but it contains two other ideas that are very interesting, because medicine in subsequent centuries has come back to them over and over again. One is that free bleeding may remove the virus, and the other that the cautery may help in preventing the infection.

" The biting of a wood-hound is deadly and venomous, and such venom is perilous. For it is long hidden and unknown, and increaseth and multiplieth itself, and is sometimes unknown to the year's end, and then the same day and hour of the biting it cometh to the head, and breedeth frenzy. They that are bitten of a wood-hound have in their sleep dreadful sights, and are fearful, astonished, and wroth without cause. And they dread to be seen of other men, and bark as hounds, and they dread water most of all things, and are afeared thereof, full sore and squeamous also. Against the biting of a wood-hound wise men and ready use to make the wounds bleed with fire or with iron, that the venom may come out with the blood that cometh out of the wound".

A very interesting development of therapeutics in the Middle Ages was the employment of the red light treatment to shorten the course and the severity of the fever in smallpox, and above all to prevent pitting; it was employed successfully by John of Gaddesden in the case of the son of King Edward II. Recent investigation by Cholmeley has shown that both Gilbertus Anglicus (1290) and Bernard de Gordon (1305) antedated John of Gaddesden in references to the red light treatment. All of these men were professors at Montpellier, showing that the medical school of the South of France was a rival in the use of natural methods of cure to its better-known predecessor of Southern Italy. Curiously enough, the " Rosa Anglica " of Gaddesden, in which the reference to the red light is made, is deservedly characterized by Garrison as " a farrago of Arabist quackeries and countrified superstitions "; it well deserves Guy de Chauliac's bitter criticism of it as " a scentless rose".

The idea included under the word autointoxication in our time—that is, that the human body has a tendency to produce poisons within itself, which act deleteriously on it and must be eliminated— was a favourite one during the Middle Ages. It became the custom in our time to have recourse to antiseptics or to surgical measures of various kinds for the relief and prevention of autointoxication. In the Middle Ages they thought to reduce its harmfulness at least by direct elimination, hence the use of drastic purgatives. It seems worth while remarking, however, that the employment of these did not come into general use until the close of the Middle Ages. Basil Valentine, if he really lived in the Middle Ages, and is not merely a name for a writer of the early sixteenth century, as modern historians seem inclined to think, suggested the use of antimony for the removal of the materies morbi from the body that has so much obsessed physicians for many generations. Antimony continued to be used down to the nineteenth century. It was gradually replaced by venesection, which was employed very strenuously during the eighteenth and early nineteenth centuries, in spite of the objection of such men as Morgagni, who refused to allow this mode of treatment to be used on him.